This invention relates to Abbe condensers and more particularly to improved Abbe condensers having excellent correction for spherical aberration and coma with significant reduction in the usual pupillary aberration.
Abbe condensers are well known and conventionally have a biconvex first element with a convex-plano second element. However, the first and second elements have been singlets except in the case of extremely complex condensers having a substantial number of additional components and usually having a triplet as the first element. Thus, microscopists either had to be satisfied with amounts of spherical aberration and coma, as well as pupillary aberration that were commonly present in conventional Abbe condensers or make a considerable investment for a complex condenser system in order to perform microscopy techniques hindered or prevented by conventional Abbe condensers.
It is an object of the present invention to provide an improved Abbe condenser.
It is another object of the present invention to provide an Abbe condenser having excellent correction for spherical aberration and coma and being well corrected for pupillary aberrations.
It is a further object of the present invention to provide an improved Abbe condenser with significantly reduced axial color aberration.
It is a still further object of the present invention to provide an Abbe condenser consisting of a biconvex positive doublet and a convex-piano positive doublet.
It is also another object of the present invention to provide an improved Abbe condenser of close working distance that can have the working distance increased by a negative lens.